1. Field of the Invention
The present invention relates to a terminal, system, and method for electrocardiogram (ECG) biometric authentication, and more particularly, to an ECG biometric authentication terminal, a biometric authentication system using the same, and a method thereof in which currents flowing in a body are generated when depolarization and repolarization occurs in an atrium/ventricle of the heart, and changes of the currents are measured and quantized to be converted into a digital binary code to facilitate determining similarities between the currents and improve reliability because similarities can only be determined through an image and a processing method is complex and unreliable when the measured changes of the currents are shown as waveforms on an analog graph such that the present invention provides a client terminal in the form of a smart watch used by coming into contact with a client's skin, changes QRS complex information unique to each individual into a digital code while extracting ECG information, and uses a Rivest-Shamir-Adleman (RSA)/Elliptic Curve Cryptosystem (ECC) algorithm to execute an authentication process by utilizing QRS complex digital ECG information as a private key of an asymmetric cryptographic system in which a public key and the private key form a pair.
2. Discussion of Related Art
Generally, a technology of utilizing various signals or data that can be extracted from a living body to use the signals or data in various types of systems is being advanced. For example, a biometric authentication technology which uses biometric signals or data to construct a security system has recently been coming into the spotlight.
A biometric authentication technology refers to a technology of authenticating a user by extracting signals or data related to a living body from the user, comparing the signals or data with pre-stored data, and confirming that the user is the user. Since the biometric authentication technology uses unique biometric signals or data of an individual unlike an identification (ID) card or a password, the biometric authentication technology is coming into the spotlight in the security field due to not having concerns of theft or loss and being difficult to forge or falsify.
In addition, the biometric authentication technology is also applicable in fields such as financial services, communication services, information security, the medical field, public safety management, and electronic commerce. In addition, although inputting a password or drawing a pattern exists as a method for authenticating a user in a portable terminal, a user authentication method using the biometric authentication technology is recently being developed to improve accuracy in authenticating a user.
Fingerprints, veins, irises, voices, faces, or lines on palms are commonly being utilized in the biometric authentication technology. Particularly, the most common method among biometric authentication methods being applied to security systems is a fingerprint recognition technology. Although fingerprints have been used for a long time as a biometric authentication method due to their characteristics of not changing for a lifetime, there is a problem in which accuracy is degraded when fingerprints are faded or dry or when fingers are stained with foreign substances.
In addition, a voice recognition technology using information on pitches of sounds according to intonations and speaking habits exist as a biometric authentication technology. Although the voice recognition technology has advantages of being able to authenticate a user even from a remote place and not requiring separate training related to a method of use, there is a disadvantage of having difficulty in authentication in a case of a hoarse throat due to cold and the like, and there is also a problem in which accuracy of authentication is degraded when others imitate a user's voice or background noise is high.
Consequently, a technology of recognizing a living body using electrocardiograms (ECGs) among biometric signals is recently being developed to solve the above problems of the biometric authentication technology.
In FIG. 1, ECG analog signals that represent normal heartbeats and electrical signals generated as a result of the heartbeats are displayed using P, QRS, T, and U waveforms.
An ECG refers to a record of electrical signals generated in the heart. A part referred to as “sinoauricular node” is present in the heart. The sinoauricular node is a particular part of the heart that controls heartbeats by cyclically generating electricity and inducing contraction of the heart.
Electrical signals generated from the sinoauricular node are transmitted throughout the heart along an electrical conduction system in the heart. Cells that form heart muscles contract due to the electrical signals transmitted to each part of the heart and cause the heart to beat. Here, a record of the electrical signals transmitted to the heart measured using electrodes attached to skin is referred to as the ECG. Electrodes are attached to various parts of the body, and an electrical phenomenon in each part of the heart can be understood well through the electrodes.
The biometric authentication technology using an ECG can be utilized in a security technology. That is, the biometric authentication technology using an ECG can be utilized as a technology for authenticating a user by extracting ECG signals from the user and comparing the extracted ECG signals with pre-stored ECG signals of a registered user. However, in this case, high accuracy of authentication is required to utilize ECG signals in user authentication and security technologies. A method of determining similarities between the extracted ECG signals of the user and the pre-stored ECG signals of the registered user is important for improving the accuracy of authentication. That is, accuracy of a method for determining similarities between the signals needs to be improved to use an ECG in a user authentication technology.
Conventionally, although image patterns have been extracted from analog ECG waveforms and the patterns have been compared to use an ECG in an authentication technology, this is unreliable since there are frequent errors in determining the similarities by comparing the image patterns.
Particularly, biometric authentication using image patterns is very insecure due to being replicable.